The issue of physical and non-physical existence, in other word the distinction between material and immaterial being is a philosophical topic that discussions about it make a radical ramification between philosophers causing them to shape different philosophical schools. In Islamic philosophy Avicenna considered this issue and adhered the distinction between physical and non- physical being. The aim in this paper is to deal with Avicenna` way on justifying and defending the rationality of belief in non- material beings. The way presented by Avicenna in his significant book called as al- Isharat- wat- Tanbihat is named by himself as the detection into sensible being. The writer argues that the method taken by Avicenna to prove that the existence is not limited to material being is not a mere subjective way rather it is an objective way. According to his view close and deep contemplation in sensible material world reveal that existence is not limited to physical beings.